EVLA Front-End CDR. Plans for S (2-4), X (8-12) & Ku (12-18 GHz) Receiver Bands

Transcription

1 EVLA Front-End CDR Plans for S (2-4), X (8-12) & Ku (12-18 GHz) Receiver Bands 1

2 Contents S-Band Receiver EVLA Design X-Band Receiver EVLA Design EVLA Transition Ku-Band Receiver EVLA Design 2

3 EVLA S-Band GHz Schedule: starting builds in 2008 Critical design issue OMT scaled from L Band quad-ridge Possible reuse L Band dewars CTI 350 cryopump is allocated 3

4 Block Diagram Quad hybrid OMT Cal injection 2 stage balanced LNA RF Postamp module 4

5 Estimated EVLA T Rx, Output Power & Headroom EVLA S-Band Rx P (1dB) P (1%) Temp NF/C Loss/Gain Loss/Gain Delta T Trx BW Pnoise Pnoise Headroom (RHH : 28 March 2006) (dbm) (dbm) (K) (db) (db) (linear) (K) (K) (MHz) (dbm) dbm/ghz (db) for Tsky of 12.0 (K) Weather Window Feed Horn Vacuum Window Quad-Ridge OMT Coax Cable Hybrid Phase Shifter Coax Cable Cal Coupler (IL) Cal Coupler (Branch) Isolator Balanced LNA (2-stage Stainless Steel Coax Coax Cable Switch Isolator Filter ( GHz) Post-Amp Isolator

6 CDL s Low Noise Amplifiers 16K performance Tamp = 4K Gain = 32 db 295K performance S11: -15dB S22: -13 db S21 S22 4K S11 6

7 Polarizer Design scaled up in frequency from L Band quadridge OMT full length = 13.25, ridge width = coax for probes 7

8 EVLA X-Band GHz Schedule: Transition receivers until 2008, new receivers Only critical design issue Polarizer CTI 22 cryopump allocated 8

9 Block Diagram polarizer undetermined cal injection cooled isolators single LNA RF postamp module 9

10 Estimated EVLA X-Band T Rx, Output Power & Headroom EVLA X-Band Rx P (1dB) P (1%) Temp NF/C Loss/Gain Loss/Gain Delta T Trx BW Pnoise Pnoise Headroom (RHH : 28 March 2006) (dbm) (dbm) (K) (db) (db) (linear) (K) (K) (MHz) (dbm) dbm/ghz (db) for Tsky of 10.0 (K) Weather Window Feed Horn Vacuum Window Phase Shifter OMT Coax Cable Cal Coupler (IL) Cal Coupler (Branch) Isolator LNA Stainless Steel Coax Coax Cable Switch Filter (7-13 GHz) Isolator Post-Amp Isolator

11 CDL s Low Noise Amplifiers 4-12 GHz LNA typical performance CX 4-12 GHz 3-stage, all InP Gain (db) C-band X-band Noise (K) 15 Gain (db) Noise (K) Frequency (GHz) 0 11

12 Polarizer Design Options Quad-ridge OMT + hybrid full length = ridge width = coax for probes 12

13 Polarizer Design Options Corrugated phase shifter + Bøifot OMT length of phase shifter 9.1 length of Bøifot OMT 8.8 better phase and amp balance than 8-12 hybrid 13

14 Polarizer Design Options Cooled dielectric phase shifter + Bøifot OMT length of PS: shorter than corrugated PS better phase and amp balance than 8-12 hybrid 14

15 EVLA Ku-Band GHz Schedule: prototype, production No critical design issues Polarizer has been designed 15

16 Block Diagram cooled phase shifter + Boifot OMT cooled isolators single LNA RF postamp module 16

17 Estimated EVLA Ku-Band T Rx, Output Power & Headroom EVLA Ku-Band Rx P (1dB) P (1%) Temp NF/C Loss/Gain Loss/Gain Delta T Trx BW Pnoise Pnoise Headroom (RHH : 28 March 2006) (dbm) (dbm) (K) (db) (db) (linear) (K) (K) (MHz) (dbm) dbm/ghz (db) for Tsky of 12.0 (K) Weather Window Feed Horn Vacuum Window Phase Shifter OMT Coax Cable Cal Coupler (IL) Cal Coupler (Branch) Isolator LNA Stainless Steel Coax Coax Cable Switch Filter (11-19 GHz) Isolator Post-Amp Isolator

18 CDL s Low Noise Amplifiers CDL model 8-18 GHz used in VLBA W Band s second stage 295K performance 16K performance 35dB 30dB S21 Gain (db) -10dB -15dB S11 S22 Noise (K)

19 Polarizer Design S. Srikanth s corrugated phase shifter shifted down in frequency from K Band model Wollack & Gundersen have designed a Ku-Band OMT Overall lengths phase shifter: 6.0 OMT:

20 More OMT Information 20

21 Conclusions S Band (2008) needs L Band OMT to scale X Band (2009) transition receivers until 2009 needs polarizer design resolved Ku Band (2007) no design issues 21